Pre-heat oven to 375F. Chop and season chicken, then cook over medium-high in olive oil until browned.
Add cream cheese, sour cream and 3/4 of the cheddar. Stir together until melted and mixed. Add tomatoes and green chili and mix well. Add everything to a casserole dish.
Microwave frozen cauliflower until cooked through. Use an immersion blender to blend with remaining cheddar cheese and parmesan into a mashed potato-like consistency. Season to taste.
Cut a jalapeno into chunks. Spread cauliflower mixture over the top of the casserole, then sprinkle jalapeno pepper over the top. Bake for 15-20 minutes.